2-12
Figure 2-8.—A properly biased PNP transistor.
PNP FORWARD-BIASED JUNCTION.—Now let us consider what happens when the emitter-base
junction in figure 2-9 is forward biased. With the bias setup shown, the positive terminal of the battery
repels the emitter holes toward the base, while the negative terminal drives the base electrons toward the
emitter. When an emitter hole and a base electron meet, they combine. For each electron that combines with
a hole, another electron leaves the negative terminal of the battery, and enters the base. At the same time, an
electron leaves the emitter, creating a new hole, and enters the positive terminal of the battery. This
movement of electrons into the base and out of the emitter constitutes base current flow (IB), and the path
these electrons take is referred to as the emitter-base circuit.
